Diagnosis of mitral valve cleft using real-time 3-dimensional echocardiography

Mitral valve cleft (MVC) is the most common cause of congenital mitral insufficiency, and MVC may occur alone or in association with other congenital heart lesions. Direct suture and valvuloplasty are the major and effective treatments for mitral regurgitation (MR) caused by MVC. Therefore, it is important to determine the location and magnitude of the pathological damage due to MVC when selecting a surgical procedure for treatment. This study explored the application value of transthoracic real-time 3-dimensional (3D) echocardiography (RT-3DE) in the diagnosis of MVC.

From October 2012 to June 2016, 19 consecutive patients with MVC diagnosed by 2-dimensional (2D) echocardiography in our hospital were selected for this study. Full-volume RT-3DE was performed on all patients. The 3D-imaging data were cropped and rotated in 3 views (horizontal, sagittal, and coronal) with 6 directions to observe the position and shape of the MVC and the spatial position between the cleft and its surrounding structures. The maximum longitudinal diameter and the maximum width of the cleft were measured. The origin of the mitral regurgitant jet and the severity of MR were evaluated, and these RT-3DE data were compared with the intraoperative findings.

Of the 19 patients studied, 4 patients had isolated cleft mitral valve, and cleft mitral valves combined with other congenital heart lesions were detected in 15 patients. The clefts of 6 patients were located in the A2 segment, the clefts of 4 patients were located in the A1 segment, the clefts of 4 patients were located in the A3 segment, the clefts of 4 patients were located in the A2-A3 segment, and the cleft of 1 patient was located in the P2 segment. Regarding the shape of the cleft, 13 patients had V-shaped clefts, and the others had C- or S-shaped clefts. The severity of the MR at presentation was mild in 2 patients, moderate in 9 and severe in 8. Two of the patients with mild MR did not undergo surgery, while the remaining 17 patients did undergo surgery. Surgical treatment involved direct suture in 11 cases, reconstruction with ring annuloplasty in 3 cases and replacement in 3 cases. The diagnoses of MVC were confirmed by intraoperative findings. RT-3DE successfully captured full-volume 3D images of the 19 patients, which directly displayed the 3D structure of MVC with multiple views such as the position, shape, longitudinal diameter and width of the MVC, and the spatial position between the chordae tendineae surrounding the MVC and the aortic valve. The maximum longitudinal diameter of the valve leaflet cleft measured by RT-3DE and direct measurements during surgery were 12.02±2.12 and 13.01±2.45 mm, respectively, and the difference between these measurements was not statistically significant (P>0.05). Our results indicate that RT-3DE can provide more direct, accurate and abundant information.

RT-3DE is a simple and fast imaging technique, and the detailed 3D images obtained can be used to confirm the diagnosis of MVC. RT-3DE is considered to be an important preoperative test that provides more comprehensive information for selecting a subsequent procedure for treatment.